MORAL FLAWS AT ODDS WITH THE PURPOSE OF TORAH
The Old Testament paints a very noble and honourable concept of Prophethood:
“…Have faith in the Lord your God and you will be upheld; have faith in his prophets and you will be successful.” [2 Chronicles 20:20]
“Although the Lord sent prophets to the people to bring them back to him, and though they testified against them, they would not listen.” [2 Chronicles 24:19]
Unfortunately the Torah presents the Prophets in an extremely negative light. No sin is too great for them to commit, nor is any vice beyond their lowly desires (you can read more about this here).
Therefore, believing that the modern Torah is uncorrupted would mean that we accept that the great Prophets of God are corrupted. This is not a viable position given the noble profile of Prophethood as defined in the Old Testament itself.